261824449 has 2 divisors, whose sum is σ = 261824450. Its totient is φ = 261824448.

The previous prime is 261824447. The next prime is 261824513. The reversal of 261824449 is 944428162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 251539600 + 10284849 = 15860^2 + 3207^2 .

It is a cyclic number.

It is not a de Polignac number, because 261824449 - 2¹ = 261824447 is a prime.

Together with 261824447, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (261824443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130912224 + 130912225.

It is an arithmetic number, because the mean of its divisors is an integer number (130912225).

Almost surely, 2^261824449 is an apocalyptic number.

It is an amenable number.

261824449 is a deficient number, since it is larger than the sum of its proper divisors (1).

261824449 is an equidigital number, since it uses as much as digits as its factorization.

261824449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 110592, while the sum is 40.

The square root of 261824449 is about 16180.9903590602. The cubic root of 261824449 is about 639.7398429922.

The spelling of 261824449 in words is "two hundred sixty-one million, eight hundred twenty-four thousand, four hundred forty-nine".